Safety apparatus for moving picture machines



Aug. 6, 1935.

F. L. NlCHOLS SAFETY APPARATUS FOR MOVING PICTURE MACHINES Filed March 20, 1953 2 Sheets-Sheet 1 [xx/wa er Fred 1. M'cfio/J 5 91 if z o rmefla Aug. 6, 1935. F. L. NICHOLS SAFETY APPARATUS FOR MOVING PICTURE MACHINES Filed March 20, 1933 2 Sheets-Sheet 2 Harvey:

Patented Aug. 6, 1935 i r v I UNITED STATES PATENT OFFICE SAFETY APPARATUS FOR MOVING PICTURE MACHINES Fred L. Nichols, Minneapolis, Minn.

Application March 20, 1933, Serial No. 661,745

BClaims. (01. 8817) My present invention relates to extremely sim-, sprockets H and H by suitable guide rollers l4. ple but very dependable and otherwise efiicient The feed rollers II, I! and I3 and film-receiving safety apparatus for moving picture projecting reel 9 may be assumed to be driven from a suitmachines, and generally stated, the invention able electric motor M illustrated only diagram- 5 consists of the novel devices, combinations of matically in Fig. 4, through suitable transmission 5 devices and arrangement of parts hereinafter demechanism, not shown. In accordance with cusscribed and defined in the claims. Among the tomai y practice, the film is fed through a guide objects of the invention is the provision of means way l5 extending beyond opposite sides of the I for preventing damaging of the moving picture projector barrel 6 and the customary film loops film by breakage or fire. The above and other l6 and I! are maintained beyond opposite sides 10 important objects and advantages of the invenof the projector and guide way. tion will be made apparent from the specifica For supplying the necessary light to the protion and claims. jector, a suitable lamp house l8 containing are In the accompanying'drawings, like characters electrodes I 9 is mounted on a supporting bracket 5 indicate like parts-throughout the several views. extending from the projector casing 1. The 5 Referring to the drawings: front of the lamp house 18 is provided with the Fig. 1 is a view in side elevation of the motion customary'condenser cone 2!, which is positioned picture projecting machine,- incorporating certo project a beam of light through an aperture tain elements of the invention, some parts of 22 in the b ck of the project r Casing directly 20 the machine being broken away or omitted, and in line with the projector cylinder 6 through a 20 some parts being shown in section; light beam receiving cone 23, the passage through Fig. 2 is a fragmentary perspective view with which is controlled by what may be assumed to some parts broken away or omitted and illus-. be a conventional rotary shutter 24. trating certain elements of the invention in con- In the ordinary operation of machines of this 25 nection therewith; type, the film loops l6 and H are normally main- 25 Fig. 3 is a detail view of one of the relay switches tained substantially as illustrated, but in some of the apparatus with some parts thereof shown instances, due to faulty film or improper threadin section, and some parts shown in full; said ing of a new film into t e a O 0 the view being taken approximately on the line 3-3 other of the loops l6 and II will be diminished of Fig. 2; and turned ninety degrees in a counor completely eliminated so that an undue ten- 30 ter-clockwise direction; sion will be placed upon the film. This tension,

Fig. 4 is a diagrammatic view illustrating the of course, places such strain on the film that electrical hook-up of the novel safety apparatus damage to th fi 0 comp breakage thereof and certain circuits controlled thereby; usually results. In cases where the film breaks Fig. 5 is a detail view with some parts broken just ahead of the intermittently driven film feed- 35 away of a safety control switch shown diagramins roller 3 a d below the light ap the matically in Fig. 4; and portion of the film in the guide way l5' above the Fig. 6 is a fragmentary detail view with some break will remain stationary and presents a seriparts broken and some parts shown in section. 0 15 fir h z since h intense beam Of light 40 The machine illustrated is of conventional dee n projected therethlough Will heat the me 40 sign and includes a projector cylinder 6 mountt a m ust m a r in a v y short ed in a casing I. Mounted on the upper porlapse of time. It will, of course, be apparent'that tion of the casing I is a film-feeding reel 8 and whenever a film breaks at some point in the mounted on the lower portion of th casing 1 machine intermediate the film feeding rollers is a similar'film-receiving reel 9. II and I2, as a result of either one or the other 45 The film indicated by I 0, is fed from the feedof the ODS a being d m nis ed, some ing reel 9 through the casing 'l and past the proportion the film will be caused to bunch D jector cylinder 6 to the film-receiving reel 9 by r wad, and in a of t s i ta es. seri us mechanism including continuously driven sprockdamage will be done to the film and a possible et-tooth-equipped feed rollers H and I2 and am serious fire hazard presented unless the film feed- 50 intermediate intermittently driven sprocketing mecha d light a are Cut ut Of tooth-equipped feed roller l3. The sprocket teeth action almost instantaneously or within a very of the film-feeding rollers Ii, l2 and I 3 work in short space of time subsequent to the break. apertures H on the edge portions of the film. It is an object of the present invention to pro- The film I0 is held in engagement with the feed vide means whereby the film feeding mechanism 55 connected to a suitable source of potential, not

shown,through a circuit comprising leads 25 and 26. The electric motor M of the film feeding mechanism is adapted to be supplied with current from a suitable source of potential, preferably separatefrom the source used by the arc electrodes l9, through a circuit comprising leads 21 and 28, and the former of which leads has interposed therein a motor service switch 29.

A. plurality of illuminating lamps, located in the building in which the projector may be assumed to be installed, and indicated individually by X, are connected in parallel to leads 3!! and 3|, the former of which is connectible to motor circuit lead 21 through either of a pair of branch leads 30 or 38'', and the latter of which connects to motor circuit lead 28.

In the preferred arrangement illustrated, a normally closed safety cut-off switch 32 is provided for emergency control of the arc, motor and general illuminating circuits. arrangement illustrated, is of the knife blade type including blades 33, 34 and 35, each pivoted to a suitable insulating base 36 at .31. For co-operation with the blades 33 and 34, are spring clip contacts 38 each mounted on the insulating base 36. The blade 35, it will be noted, is provided beyond 'its'pivot point 3-| with an extension- 39 which co-operates with but is normally disengaged from a spring clip contact 48 also mounted on the insulating'base 36. The blades 33 to 35, inclusive, are all connected for common movements by means of a tie-bar 4| of suitable insulating material and which tie-bar is formed or otherwise provided with a handle 42 for convenient manual manipulation of the switch.

By reference now to the arc electrode and motor circuits, it will-be noted that the lead 26 of the electrode circuit includes and is normally closed through the switch blade 33 and its cooperating spring contact 38 and the motor circuit lead 21 includes and is normally completed by switch blade 34 and its co operating spring clip contact 38. 7

The general illumination circuit may be closed at any time by manipulation of a service switch 4| located in 'the branch lead 30*, and which is normally open when the projecting machine is in operation, for general illumination is not desired at that time. The general illuminating circuit is automatically completed when leads 33 and 34 of the safety cut-off switch are opened in respect to their co-operating contacts 38 through branch lead 3|! and normally open blade and contact 39 and 48, respectively, which latter are automatically closed when the switch blades cuits are closed therethrough to a position wherein said circuits are opened, and the general illuminating circuit is closed, when improper feeding of tho film through the machine occurs,

This switch 32, in the 7 that project from the bases 62.

I provide the highly eflicient system hereinafter immediately described, and which includes a relatively strong pull solenoid 43, the plunger 44 of which solenoid is suspended from the crossbar 4| of the switch 32 through connections including a link 45 and a bracket 46. The link 45 is pivotally connected to the plunger 44 at 41 and the other end portion thereof works through the bracket 46 for movements that are limited by nuts 48 and 49, and a compression spring 58 that has preferably just sufiicient strength to support the plunger without being appreciably compressed.

The switch blades 33 and 34 are manually closed with their respective spring contacts 38 and are normally held in that position by the frictional engagement of the contacts, which may be assumed to be sufiicient to support the weight of the plunger 44. Obviously, with the switch 32 and actuating mechanism illustrated, the switch blades 33 and 3.4 will remain engaged with their respective contacts 38, until the solenoid 43 is energized and, at that time, the plunger 44 will have sufficient magnetic pull exerted thereon to free the blades 33 and 34 from their respective contacts 38, and aided by the action of gravity, to

move the projecting end of the blade 35 into engagement with its co-operating spring clip contact 40, thereby opening the motor and are electrode circuits and closing the general illumination circuit.

Current for energizing the safety cutoft switch actuating solenoid 43 is supplied from the motor circuit leads 2! and 28 through either of a pair of like circuits, each of which includes and is 'controlled by a like film-operated relay switch 5| and 52. Each of these relays 5| and 52 includes a pivoted switch arm 53 carrying a contact 54 and a relatively fixed but adjustable contact 55. The solenoid supply circuits through each of the relay switches 5| and 52 includes a lead 56 extending from the motor circuit lead 21, and common to both circuits, branches 5! and 58 from the lead .56, the former having interposed therein the rethe solenoid 43 to the motor circuit lead 28 through illuminating circuit lead 3|.

switch arms 53 of the relay switches are each piv-- oted at 6| to a bracket 6| that is mounted on an, insulated base 62 and the fixed contacts 55 of said switches are adjustably mounted in brackets 63 The arms 53 of the relay switches are normally yieldingly held in a position wherein their contacts 54 are spaced slightly from their respective fixed contacts and against adjustable stops 54 by light tension springs 65. One projected end of the switch arm of each relay switch overlies and spaced from an'electro-magnet 66, which, wh properly energized, have sufficient power to cl se and maintain relay switches-firmlyplosed. The various elements of each relay-switch and its respective 00- operating magnet is-enclosed in its own case are free to-work in slots 68.

through which the arms 53 thereof-project and The circuit of each electro-magnet 66 includes the common relay switch circuit lead 56, part of its co-operating relay switch branch lead 51 or 58, is 'co -operating' relay switch 5 I or 52, a lead 69 branching'from a-branch lead 51 or 58 at a point beyond need-operating relay switch 5| or 52 and connecting thereto, and a lead extending therefrom to a common lead ll through which and the lead 60 connection is made to the motor circuit lead 28.

' The cases 61 containing the relay switches II and 52 and their respective electro-magnets 33 are suitably mounted at the exterior of the projector machine casing i, and in the preferred arrangement illustrated, the case containing the relay switch 5! is located in the vicinity of the film loop 16 and the case containing the relay switch I! is located in the vicinity of the lower film loop l1. Carried bybut electrically and magnetically insulated from the switch arm 53 of each relay switch 5| or 52 at 12 is a film-actuated switch arm extension 13 preferably of non-magnetic material, such as brass, having an offset free end portion 13 The extension 13 of the arm 33 of the relay switch 5| works axially through an aperture I4 in the casing I of the projector with its offset free end portion I3 extended into the film loop IS. The oifset free end portion 13' of the extension 13 of relay switch I3 works through a slot 15 in the projector casing I and extends intothe film loop l1.

It will now be evident that when either of the film loops it or i! become materially diminished, a cooperating relay switch Si or 52 will be closed, thereby completing the supply circuit to the solenoid 4a and the circuit through its co-operating electro-magnet 38. The co-operating electromagnet 66, upon being energized, will exert considerable pull on the overlying end portion of the relay switch arm 53and will hold the relay switch contacts 54 and 55 firmly closed.

The safety switch-operating solenoid 43, upon being energized, will pull the blades 33 and 34 of the safety cut-out switch 32 out of engagement with their co-operating spring clip contacts 38, thereby opening the circuit of the arc electrodes l3 and the motor circuit, and the action of said solenoid 43, aidedby the action of gravity, will continue movement of the switch blades 33 to 35, inclusive, until the projecting end 33 of the blade 35 is brought into engagement with its co-operating spring clip contact 40, thereby closing the supply circuit for the general iilumination lamps x. The circuit of the filmfeeding motor M, is in this manner interrupted before a diminishing film loop l3 or I1 is completeiy eliminated, so that the film-feeding mechanism is rendered inoperative and comes to a stop before damaging tension is exerted on the film,

and since the circuit of the arc electrodes II is interrupted simultaneously with opening of the motor circuit, the intense beam of light normally projected through the film is cut off before the film is heated to a combustible temperature thereby, even though a portion of the film should come to a stand-still in front of the light aperture 22. Not only will the relay switches II or 52 be closed-by diminution of a film loop N or H, but also if ballooning of a film loop occurs.

' the resultant bunching up of the film in the v i-.

cinity of a normally looped portion of the film will cause closing pressure to be exerted on the adjacent relay switch arm extension 13' and the mechanism will be immediately rendered inoperative and usually before any material damage has been done to the film.

It will, of course, be understood that the relay switches and their operating connections may be located adjacent any portion of a path normally travelled by the film through the machine, where it is found that the film is apt to leave its normal path and, further, that relay switches may be strength to maintain the relay switches closed firmly until the circuit therethrough is broken, and which breaking of the circuit does not, of course, occur until the motor and are electrode circuits have been opened. The relay switches must, in a device of this character, close the circuit through the solenoid 43 for a sufiicient period of time to cause complete withdrawal of the switch-blades 33 and 34 from their co-operating contacts 33 and that such action might not resuit from a very short closing period of a relay switch or an intermittent series of short closings thereof. With this arrangement, however, the complete operation of the safety cut-off switch 32 is insured since the relay switches once closed are caused to remain closed during a comchine provided with a projector, a film, meansincluding an electric motor and parts driven therefrom for moving the film past the projector, and a supply circuit for the said motor, of a normally closed safety cut-off switch in the motor supply circuit, an electro-magnetic actuator for the said safety control switch, a supply circuit for said safety switch actuator, a normally open relay switch interposed in and controlling the supply circuit of the said safety switch actuator and having an operating element extending into close relation to the path normally travelled by the film where it will be engaged by the film and caused to close the said relay switch when vand only when the film leaves its normal path,

that when energized as a result of even momentary relay switch closing pressure exerted by the film, it will close and hold closed the said relay switch during the complete period of op cation of the safety cut-off switch actuating means.

2. The combination with a motion picture ma chine provided with a projector, a film. means including an electric motor for moving the film safety control switch means, a supply circuit for said electro-magnetic actuator, a normally open relay switch'interposed in and controlling the said circuit of the eiectro-magnetic safety switchactuating means and having an operating element extending into close relation to the path normally travelled by the film where it will be engaged by the film and moved thereby to close the relay switch when and only when the film leaves its normal path, and an electro-magnetic device connected tobe operated from the supply circuit of the safety control switch-actuating means-and to be controlled by said relay switch and operative when energized as a result of even momentary relay switch closing pressure exerted by the film to retain'the relay switch closed during the complete period of operation of the safety control switch operating means.

3. The structure defined in claim 1 in which the supply circuit of the electro-magnetic safety switch actuator is controlled by the said safety control switch, whereby it will be opened when the motor circuit is open.

4. The structure defined in claim 2 in which the supply circuit of the electro-magnetic safety switch actuator is controlled by the' said safety controlled switch, whereby it will be opened when the motor and lamp circuits are opened.

5. In a motionpicture projecting apparatus, the combination with a film, means for projecting a beam of light through the film, and means for moving the film past the'projector, of meansfor cutting off the beam-of light to the film. an electro-magnetic actuator for said light beam cut-oil, a supply circuit for said electro-magnetic actuator, a normally open relay switch interposed in andcontrolling the supply circuit of said relay switch when and only when the film leaves its normal path, and an electro-magnetic device connected to be operated from the circuit of and controlled by the relay switch and operatively arranged so that when energized as a result of even momentary relay switch closing prasure, exerted by the film, it willclo'se and hold closed the said relay switch during the complete 1 the safety switch-actuat:

circuit of the said electro-magnetic actuator and having an operating element extending inclose relation to the path normally travelled by the film where it will be engaged by the film and caused to close the relay switch when-and only when the film leaves its normal path, and an electro-magnetie device connected to be operated from the circuit of and controlled by the relay switch and operatively arranged so that when energized as a result or even momentary relay switch-closing pressure exerted by the film, it will close and hold closed the said relayrswitch during the complete period of operation of the electro-magnetic actuator. 7

Farm 1.; rfncnors. 

